/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.aop.support;

import org.aopalliance.aop.Advice;
import org.springframework.aop.Pointcut;
import org.springframework.lang.Nullable;
import org.springframework.util.ObjectUtils;

import java.io.Serializable;

/**
 * Convenient class for regexp method pointcuts that hold an Advice,
 * making them an {@link org.springframework.aop.Advisor}.
 *
 * <p>Configure this class using the "pattern" and "patterns"
 * pass-through properties. These are analogous to the pattern
 * and patterns properties of {@link AbstractRegexpMethodPointcut}.
 *
 * <p>Can delegate to any {@link AbstractRegexpMethodPointcut} subclass.
 * By default, {@link JdkRegexpMethodPointcut} will be used. To choose
 * a specific one, override the {@link #createPointcut} method.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @see #setPattern
 * @see #setPatterns
 * @see JdkRegexpMethodPointcut
 */
@SuppressWarnings("serial")
public class RegexpMethodPointcutAdvisor extends AbstractGenericPointcutAdvisor {

    private final Object pointcutMonitor = new SerializableMonitor();
    @Nullable
    private String[] patterns;
    @Nullable
    private AbstractRegexpMethodPointcut pointcut;


    /**
     * Create an empty RegexpMethodPointcutAdvisor.
     *
     * @see #setPattern
     * @see #setPatterns
     * @see #setAdvice
     */
    public RegexpMethodPointcutAdvisor() {
    }

    /**
     * Create a RegexpMethodPointcutAdvisor for the given advice.
     * The pattern still needs to be specified afterwards.
     *
     * @param advice the advice to use
     * @see #setPattern
     * @see #setPatterns
     */
    public RegexpMethodPointcutAdvisor(Advice advice) {
        setAdvice(advice);
    }

    /**
     * Create a RegexpMethodPointcutAdvisor for the given advice.
     *
     * @param pattern the pattern to use
     * @param advice  the advice to use
     */
    public RegexpMethodPointcutAdvisor(String pattern, Advice advice) {
        setPattern(pattern);
        setAdvice(advice);
    }

    /**
     * Create a RegexpMethodPointcutAdvisor for the given advice.
     *
     * @param patterns the patterns to use
     * @param advice   the advice to use
     */
    public RegexpMethodPointcutAdvisor(String[] patterns, Advice advice) {
        setPatterns(patterns);
        setAdvice(advice);
    }


    /**
     * Set the regular expression defining methods to match.
     * <p>Use either this method or {@link #setPatterns}, not both.
     *
     * @see #setPatterns
     */
    public void setPattern(String pattern) {
        setPatterns(pattern);
    }

    /**
     * Set the regular expressions defining methods to match.
     * To be passed through to the pointcut implementation.
     * <p>Matching will be the union of all these; if any of the
     * patterns matches, the pointcut matches.
     *
     * @see AbstractRegexpMethodPointcut#setPatterns
     */
    public void setPatterns(String... patterns) {
        this.patterns = patterns;
    }


    /**
     * Initialize the singleton Pointcut held within this Advisor.
     */
    @Override
    public Pointcut getPointcut() {
        synchronized (this.pointcutMonitor) {
            if (this.pointcut == null) {
                this.pointcut = createPointcut();
                if (this.patterns != null) {
                    this.pointcut.setPatterns(this.patterns);
                }
            }
            return this.pointcut;
        }
    }

    /**
     * Create the actual pointcut: By default, a {@link JdkRegexpMethodPointcut}
     * will be used.
     *
     * @return the Pointcut instance (never {@code null})
     */
    protected AbstractRegexpMethodPointcut createPointcut() {
        return new JdkRegexpMethodPointcut();
    }

    @Override
    public String toString() {
        return getClass().getName() + ": advice [" + getAdvice() +
                "], pointcut patterns " + ObjectUtils.nullSafeToString(this.patterns);
    }


    /**
     * Empty class used for a serializable monitor object.
     */
    private static class SerializableMonitor implements Serializable {
    }

}
